The Desk Mount plate is 6 inches x 2.5 inches. With four 1/4 inch holes 2.5 inches apart length wise, 1.25 inches apart width.
The mounting screws are #12 wood screws 3/4 inch long. the threads from the bottom of plate to tip of screw is 9/16 inch.
We have successfully mounted the Desk Mount on the metal book tray of a students desk with machine screws.